What the Anesthesiologist Should Know before the Operative Procedure

During uterine curettage, an instrument is used to scrape or suction the uterine lining to diagnose and/or treat abnormal bleeding or to remove products of conception. If not already dilated, the cervix must first be opened mechanically or chemically.

The indication for the dilation and curettage is an important concern for the anesthesiologist. An acute hemorrhage situation requiring an emergent or urgent dilation and curettage requires additional setup and has higher risks, while a diagnostic elective procedure typically has lower risks. Therefore, it is important for the anesthesiologist to know the indication for the procedure.

The complications associated with this procedure, which consist primarily of bleeding and uterine perforation, occur at a frequency of approximately 1-2%. In order to maximize the diagnostic and therapeutic yield and minimize risk, Dilation and Curettage (D & C) or Dilation and Evacuation (D & E) can be substituted by non-invasive procedures (such as transvaginal ultrasound) when appropriate, or augmented with more directed techniques, such as hysteroscopy and/or polypectomy.

The causes of uterine bleeding leading to curettage include:

1) Pregnancy-related issues, such as miscarriage, retained products of conception, or therapeutic abortion.

2) Non-pregnancy-related issues, such as investigation of fibroids or polyps or hyperplastic uterine linings.

1. What is the urgency of the surgery?

What is the risk of delay in order to obtain additional preoperative information?

D & Cs or D & Es are elective, outpatient procedures if there is no major bleeding and/or if the procedure is done for diagnostic purposes.

Emergent: If the patient is having active and ongoing bleeding resulting in subjective symptoms, such as lightheadedness or palpitations, or is showing objective signs of significant hypovolemia, such as hypotension or tachycardia, then the D & C should be performed as soon as possible. Delaying curettage may result in exsanguination. Practitioners should be prepared for major resuscitation that includes crystalloids, colloids, and blood products (in some cases, uncrossed-matched RBCs) as needed. Depending on the source of bleeding, the procedure may need to be converted to a laparoscopy or laparotomy.

Urgent: Patients with chronic bleeding are often evaluated first by imaging (e.g. ultrasound) to inform the decision of whether or not to proceed with D & C. There is typically time for these patients to undergo a more thorough preoperative evaluation and for blood to be typed and crossed, if needed.

Elective: Patients with intermittent, abnormal vaginal bleeding, uterine fibroids, or polyps may undergo D & C as an elective procedure. These procedures are typically used to determine the cause of bleeding and, in some cases, the benign or malignant nature of a uterine growth. These patients can undergo pre-operative testing based on the presence or absence of co-morbidities.

2. Preoperative evaluation

During the preoperative evaluation, it is important to assess the pregnancy status of the patient, as dilatation and curettage is contraindicated in patient with a viable and desired intrauterine pregnancy.

Medically unstable conditions warranting further evaluation include major cardiac or pulmonary disease or clotting disorders. Patients with pelvic infections are at risk for bacteremia and perforation as a result of the fragile uterine tissue.

In general, cardiac testing is unnecessary for asymptomatic patients. Delaying surgery may be indicated if the patient is pregnant and this is not a pregnancy-related D & C or if the procedure is elective and the patient is unstable because of comorbid illness. The patient should be optimized prior to proceeding with surgery, if feasible, if she had cardiac issues, such as unstable angina, and if significant intra-operative bleeding is expected.

Patients with severe hip arthritis can be difficult or impossible to position in stirrups (i.e. lithotomy), thus limiting the feasibility of these procedures.

Patients with pre-existing cardiac, gastrointestinal, or pulmonary issues may benefit from regional or paracervical blocks. It would be important to evaluate these patients preoperatively for coagulation disorders or infection near the block site.

3. What are the implications of co-existing disease on perioperative care?

Perioperative evaluation

Patients with acute or chronic bleeding should have a baseline CBC. If bleeding has been significant (>=1.5 liters acutely, or multiple recent bleeds), then consider a DIC screen.

b. Cardiovascular system

Acute/unstable conditions

Acute ongoing hemorrhage may exacerbate underlying cardiac ischemia, further necessitating prompt resuscitation and identification of the underlying cause of bleeding.

Baseline coronary artery disease or cardiac dysfunction

Goals of management: If the patient's pain and bleeding are well controlled, then the D & C or D & E should lead to minimal hemodynamic derangement. However, inadequate anesthesia and major hemorrhage can precipitate ischemia through increased utilization and decreased availability of oxygen.

c. Pulmonary

COPD

Perioperative Evaluation

Patients with a significant smoking history, chronic bronchitis, or baseline oxygen requirements should be identified preoperatively. Patients with acute or chronic alcohol use can have increased risk for aspiration and more colonization with pathologic bacteria in their airway. Unless an acute COPD exacerbation is suspected, additional preoperative testing is rarely indicated.

Perioperative Risk Reduction Strategies

These targeted patients should continue their ongoing medication regimens, assuming they are optimized. Patients with COPD may benefit from short term preoperative inhaled or systemic corticosteroids. Anesthetic techniques that avoid instrumenting the airway, such as a paracervical block with sedation or neuraxial anesthetics, are preferable to general anesthesia. Patients with a history of smoking or excessive alcohol consumption should be advised to practice smoking and alcohol cessation at least 4-8 weeks prior to surgery.

Reactive Airway Disease (i.e., Asthma)

Perioperative Evaluation

The status and severity of the patient's disease should be assessed, including identifying common triggers, the response to bronchodilators, history of recent hospitalizations, prior steroid therapy, or intubations for exacerbations.

Perioperative Risk Reduction Strategies

Ideally, patients would not undergo a procedure during an asthma or COPD exacerbation, but rather they would first be medically optimized. If the procedure is emergent, the anesthetic technique of choice would be to allow the patient to breathe spontaneously and avoid instrumentation of the airway (e.g. paracervical block with sedation/MAC or spinal). If general anesthesia is necessary, then initial use of a volatile agent to aid in bronchodilation, decreased to 0.5 MAC after induction to promote uterine contraction post-procedure, would be beneficial. Preoperative and intraoperative treatment with inhaled bronchodilator therapy may also benefit these patients. In situations with excessive bleeding, carboprost (Hemabate) should be avoided or used cautiously as it can cause bronchospasm in susceptible individuals. Alternative uterotonic agents such as oxytocin, methergine, or misoprostol should be used instead.

Post-operative

Active respiratory therapy is advisable.

d. Renal-GI:

As per ASA guidelines, patients undergoing non-urgent or emergent D & C should be NPO for 6-8 hours for solid food and 2 hours for clear liquids prior to the procedure. Those with symptomatic reflux should be identified, and should undergo light sedation that preserves airway reflexes (+ paracervical block or neuraxial anesthetic) or rapid sequence induction with general endotracheal anesthesia after H2 blocker therapy.

e. Neurologic:

N/A

f. Endocrine:

N/A

g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (e.g., musculoskeletal in orthopedic procedures, hematologic in a cancer patient)

Patients with a history of or active cervical or uterine cancer should be evaluated preoperatively and managed carefully as heavy bleeding or perforation can occur. The anesthesiologist should be prepared with proper IV access and blood products on standby.

4. What are the patient's medications and how should they be managed in the perioperative period?

N/A

h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?

If patients are taking anti-coagulants or anti-platelet agents, they should consult with their physicians at least a week prior to surgery for further instructions, as some of these medications have an extremely long half-life.

i. What should be recommended with regard to continuation of medications taken chronically?

Cardiac

continue

Pulmonary

continue

Renal

continue

Neurologic

continue

Anti-platelet

consult with multidisciplinary team

Psychiatric

continue

j. How To modify care for patients with known allergies -

N/A

k. Latex allergy- If the patient has a sensitivity to latex (e.g., rash from gloves, underwear.) versus anaphylactic reaction, prepare the operating room with latex-free products.

In case of anaphylaxis, epinephrine, IV H1, H2 blockers and steroids, and rescue airway equipment should be readily available.

Local anesthetics

These are not considered to be MH triggering agents, and therefore can be used in patients at risk for malignant hyperthermia. It is important to ask patients if they are allergic to local anesthetics or sunscreen containing PABA (relevant for ester local anesthetics) before administering local anesthetic.

5. What laboratory tests should be obtained and has everything been reviewed?

For young healthy patients not at risk of significant bleeding, no pre-operative labs are needed unless there is significant hemorrhage.

Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?

The anesthetic options for dilation and curettage include conscious sedation or MAC (monitored anesthesia care) +/- paracervical block, neuraxial, and general anesthesia. The optimal anesthetic choice depends on the patient and:

a) the degree of hemorrhage/hemodynamic stability,

b) the patient and provider preference,

c) and cervical dilation, which may affect the feasibility of doing a paracervical block.

The available evidence fails to show whether paracervical block is inferior, equivalent to, or superior to alternative analgesia techniques in terms of efficacy and safety for women undergoing uterine interventions.

a. Regional anesthesia

1. Neuraxial

Benefits: anecdotally, patients typically feel the least discomfort.

Drawbacks: low, but non-zero, risk of post-dural puncture headache (PDPH) and transient radicular irritation (TRI) in setting of outpatient procedure and lithotomy position. Consider using hyperbaric bupivacaine 0.75% (1-1.5 ccs) with fentanyl (10-20 mics) or, if less than 1 hour of procedure time is anticipated, mepivacaine 1.5% (45-60 mg) with preservative-free dextrose (approximately 1 cc) or chloroprocaine 40-60mg. Recovery time varies and the patient may have to recover in hospital before being discharged.

2. Peripheral Nerve Block

e.g., paracervical (consider Nesacaine 1%)

Benefits: less invasive and better analgesia than sedation alone.

Drawbacks: reports of pain regardless of the agent used if paracervical block is done without sedation.

Intrauterine analgesia

Benefits: less invasive. Some investigations have shown that 5 cc's of 2% lidocaine can be as effective as paracervical block or po NSAID. As with paracervical block, use in conjunction with conscious sedation for best results.

b. General Anesthesia

Drawbacks: potential airway issues or increased risk of aspiration if patient is beyond the first trimester of pregnancy or recently post-partum. Increased risk of postoperative nausea and vomiting.

c. Monitored Anesthesia Care

D & C is often done under sedation or Monitored Anesthesia Care (MAC) with paracervical block.

There are many analgesia and anesthetic agents that can be used in bolus dosing or as continuous infusions (e.g., Fentanyl and Versed, Propofol and Remifentanil). In one randomized, controlled trial, propofol (target concentration of 5 mics/ml) was recommended for D & C when administered with Fentanyl 1 mic/kg and N02 (66%) as compared with 4 and 6 mics/cc. Close monitoring and appropriate respiratory management were deemed necessary for safe administration.

Benefits include that it takes the patient less time to wake up when compared with general anesthesia, potentially less need to instrument the airway, if the patient continues to breath spontaneously, and the avoidance of post-dural puncture headache.

Drawbacks include the risk of respiratory depression, which could lead to depressed airway reflexes, aspiration, and/or apnea, the potential for patient movement, increasing the chance of uterine perforation, and a greater chance of inadequate pain relief when compared to neuraxial or general anesthesia.

6. What is the author's preferred method of anesthesia technique and why?

When obstetric providers expect that the procedure will be straightforward (that is, there is no molar pregnancy or malplacentation) for first trimester incomplete or therapeutic abortions or the removal of retained products of conception, then our anesthetic of choice is a paracervical block placed by the surgeons (using 1% Nesacaine) and MAC. We use various combinations of anesthetics for sedation during the MAC, including bolus fentanyl and versed or propofol and remifentanil infusions.

For second trimester D & Es, our anesthetic of choice is typically either spinal or general (endotracheal) anesthesia, and occasionally MAC plus paracervical block The MAC with paracervical block option requires careful case selection (e.g., absence of symptomatic reflux in the patient, anticipation of a straightforward procedure).

If significant bleeding has occurred or is expected, or if the patient is hemodynamically unstable, then we proceed with resuscitation and general endotracheal anesthesia. If the uterus needs to be evacuated urgently, but the patient has recently ingested food other than clear liquids or has an active upper respiratory infection, we will proceed with a spinal anesthetic with light-to-moderate sedation if no contraindications, such as coagulopathy or hemodynamic instability, exist.

If there are no contraindications and no objections by the surgical team, interoperative ketorolac 30mg is given IV for postoperative pain control. Patients are continued on NSAIDs postoperatively on an as-needed basis for pain control.

What prophylactic antibiotics should be administered?

According to the ACOG guidelines, despite the lack of data, antibiotic prophylaxis is indicated for elective and missed suction curettage abortion. Although the optimal antibiotic regimen is unclear, Doxycycline (100 mg prior to the procedure and 200 mg post-procedure) was shown in a meta-analysis to be effective and inexpensive. In a prospective, randomized, controlled trial, antibiotic prophylaxis showed no benefit before the treatment of incomplete abortion.

What do I need to know about the surgical technique to optimize my anesthetic care?

Will there be manual dilation of the cervix?

In general, dilation is painful and requires a significant degree of anesthesia (i.e., a functional paracervical block, spinal, or general anesthesia).

Will this be a first or second trimester gestation?

In general, second trimester D & Es are more complex and are less conducive to MAC.

What can I do intraoperatively to assist the surgeon and optimize patient care?

During manual dilation of the cervix and active curettage, it is important that the patient not move her hips or lower extremities, as movement can increase the risk of uterine perforation. As such, the patient should either be conscious and able to control her own body or sedated enough to restrict movement (e.g., during a GET).

What are the most common intraoperative complications and how can they be avoided/treated?

Hemorrhage

Attention to pre-op volume status and intra-op bleeding is essential. In the case of straight-forward first trimester missed Ab, the bleeding is often self-limited. Patients with chronic uterine bleeding or retained products of conception requiring D & E can often require significant resuscitation, including blood products such as PRBCs, FFP, platelets, and Cryoprecipitate, if bleeding is severe.

Uterine Perforation

As with any change in patient status, suspected uterine perforation should prompt direct and specific communication between the surgery, nursing, and anesthesia teams. Minor perforation can have little to no effect on the patient's intra-op course, while major perforation can require urgent laparotomy and precipitate significant hemorrhage.

Uterine perforation is of higher likelihood in procedures done to treat uterine bleeding as opposed to diagnostic dilatation and curettage. Risk of perforation is also increased in pregnancy.

Cardiac/Pulmonary Complications

Amniotic Fluid Embolus (AFE) has been reported in pregnancy-related D & E. Therapy involves supportive care; in cases of cardiac or respiratory collapse, cardiopulmonary bypass or ECMO have been employed in some isolated cases. In general, morbidity and mortality is high with AFE.

a. Neurologic

Patients who have outpatient procedures in the lithotomy position under spinal anesthesia have an increased incidence of Transient Radicular Irritation (TRI).

b. If the patient is intubated, are there any special criteria for extubation?

If there has been significant hemorrhage and resuscitation, it is important to assess tissue swelling and airway swelling before extubation.

c. Postoperative management

What analgesic modalities can I implement?

If not otherwise contraindicated, NSAIDS (e.g., Toradol) +/- opioids are particularly useful for post-D & E pain management, given the high incidence of uterine cramping.

What level bed acuity is appropriate?

Unless there has been significant hemorrhage, D & E is often done as an outpatient procedure. Those patients who have required significant resuscitation may need to be in an inpatient setting overnight; in this case, the patient's underlying health status and degree of hemodynamic stability post-procedure can be used to decide whether she needs a monitored bed (e.g. step-down Unit or ICU).

What are common postoperative complications, and ways to prevent and treat them?

To prevent post-operative bleeding, patients will sometimes be given intra-operative uterotonic agents as well as resuscitation with crystalloids or blood products as needed. Those with suspected uterine perforation are often treated with antibiotics. The development of TRI after spinal anesthetic is typically a relatively benign and self-limited event.

(In this randomized, double-blind study, intraoperative pain was better, although still elevated, when ropivacaine was used for paracervical block compared with lidocaine. Postoperative pain was not different between the two groups.)

(Either intrauterine lidocaine (5 cc's 2% lidocaine) or oral dexketoprofen were effective in relieving fractional curettage-related pain, although a combination of the two medications did not demonstrate a clinically relevant increase in analgesia.)

(This randomized, double-blind, controlled study showed that the addition of intrauterine anesthesia (in this case 5ml 2%lidocaine in addition to the paracervical block) further reduced pain during D & C without increasing side effects.)

(Complete evacuation of the uterus was more common if surgical management was undertaken than if there was medical management of first trimester or incomplete miscarriage. Expectant management had very variable success rates.)

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